Tooth structure

A tooth is made up of two parts. The crown is the top part of the tooth that's visible in the mouth. The root extends into the bone of the jaw, anchoring the tooth in position.

Teeth also consist of:

enamel – the hard outer coating

dentine – a softer material that supports the enamel and forms most of the tooth

cementum – a hard material that coats the root's surface

dental pulp – the soft tissue at the centre of the tooth

The root canal system contains the dental pulp and extends from the crown of the tooth to the end of the root. A single tooth can have more than one root canal.

When root canal treatment is needed

Root canal treatment is only required when dental X-rays show that the pulp has been damaged by a bacterial infection. The pulp will begin to die if it's infected by bacteria, allowing the bacteria to then multiply and spread.

The symptoms of a pulp infection include:

pain when eating or drinking hot or cold food and drink

pain when biting or chewing

a loose tooth

As the infection progresses, these symptoms often disappear as the pulp dies. Your tooth then appears to have healed, but the infection has in fact spread through the root canal system.

Further symptoms eventually occur, such as:

pain when biting or chewing returning

swelling of the gum near the affected tooth

pus oozing from the affected tooth

facial swelling

the tooth becoming a darker colour

It's important to see your dentist if you develop toothache. If your tooth is infected, the pulp can't heal by itself.

Leaving the infected tooth in your mouth may make it worse. There may also be less chance of the root canal treatment working if the infection within your tooth becomes established.